Accidental pricking is a serious problem for persons who must handle hypodermic needles. The pricking is most apt to occur to the fingers that hold a needle cover, in the act of replacing the cover, and almost all covers must be replaced, even for disposable needles for it is hazardous to throw a used syringe into the trash with an exposed needle. Needles with plastic needle covers are used in large quantities and in standard sizes and shapes. Widely used disposable insulin needles have covers of ridge lined cylindrical shape, with flanged tops, while most, including luer lock, other needles have tapered covers, varying in length to fit different length needles but being provided in a short range of diameters.
When the needles are re-covered it is usually after they have been removed from a patient and are contaminated with the patient's microorganisms, such, possibly, as AIDS virus. It is thus a matter of grave concern to nurses and hospital assistants that they be protected from the danger of pricking their fingers when they replace a needle cover. The covers, however, present a very small target when held in one's hand, and if this target is missed by the syringe needle, a dangerous skin breaking by the contaminated needle is almost inevitable. In practical terms there has been no solution to this problem prior to the present invention.